So as soon as the trans get any volts don't even have to be running it goes straight to third. It say 3-4 shift solenoid, trans fluid temp sensor to high, governor pressure voltage to high. So i went through and replace all the solenoids and sensors in the trans and still same.prob. so bougjt a pcm...nothing. new ats valve body...nothin. trans was rebuilt bout 3 months ago..

This prob just randomly started one day and havent been.able to drive since. The day before i drove it no problems, had all my gears.

 

I have you disconnected the batterys and reset the codes? I'm not sure on the 12V if they have the speed sensors on the rearend. The third gear start is limp mode I know that. My wife's Durango did this put in a new Trans after recommended by shop and still didn't fix the limp mode they had to replace another sensor some where but I was home and didnt get to talk with them about it wife picked up the truck. It was also a 2001 model. I know it wasn't on the Trans.